In recent years the sail making industry has adopted laminated sailcloths incorporating scrims of high modulus materials to reinforce the underlying sailcloth. These laminates have consisted of one or more layers of nonwoven plastic film (such as polyester, nylon or tedlar) adhered to the sailcloth substrate. Another approach has been to provide a woven ply on the sailcloth substrate and adhering the two plies together. See for example U.S. Pat. No. 4,554,205 issued to Peter Mahr in 1985.
These types of laminated sailcloth are designed to minimize the stretch of the cloth in the sail under wind loading by providing the reinforcements in line with the high load directions within the sail. The film on the sailcloth controls the stretch in the bias direction (that is in a direction at an angle between the warp and the weft thread line directions). Experience has shown that these laminated sailcloths eventually delaminate with age, use and exposure to the elements. In addition, the films used tend to crease and exhibit a shrinkage with use which tends to degrade the designed in shape provided by the sailmaker so that the sail will assume that shape when deployed.
The object of the present invention is to provide a single ply woven sailcloth capable of absorbing wind loadings both in the direction of the thread line yarns and in the bias direction without the use of laminates.